1. Recent advances in rumen manipulation
techniques with particular reference to
ruminant production
By : Tetemke Kidane

2. INTRODUCTION
• Why do we need to manipulate the rumen?
• 15 to 20% of GEI is lost in the form of methane
and heat due to rumen fermentation
• 8 -10 % of dietary ME lost as methane -
methanogenic bacteria
• Amino acids are hydrolyzed and their constituent
amino acids deaminated by microbes
• manipulate the microbial population to minimize
the degradation of feed protein

3. Cont’d…
• use of chemicals inhibit the activity of
microbial proteases or deaminases
treatment of feedstuffs
inhibit ruminal proteolysis
various drying procedures, heat
 Formaldehyde-treated feeds - increases
efficiency of growth
 use of some proteins to coat and protect fat
• To enhance yields of milk and to increase amounts
of USFA in milk or animal fat.

4. The digestive tract of a health adult ruminant
(Source: Russell, 2000)

5. The rumen microbes
• Bacteria- gram-positive and gram-negative
• most numerous group of microbes in the rumen
• Substrates are fermented to form volatile fatty acids
(Acetate, Propionate, Butyrate and others) and C02
and CH4
• Protozoa
• Generally larger than bacteria but present in small no.
• Fibre digestion
• Negatively influence protein utilization – predation
and reduce outflow of microbial protein
• Ruminants can survive with out protozoa
• Fungi
– recently discovered ruminal MOs
– Degrade the lignin-containing tissues than bacteria

6. livestock agriculture’s role in greenhouse
gases
CH4 % of
million metric % of
anthropogenic
Sources tons/yr total sources
Natural
Wetland 115 24.4 -
Oceans 15 3.2 -
Termites 20 4.2 -
Burning 10 2.1 -
Industrial
Gas and oil 50 10.6 16.1
Coal 40 8.4 12.8
Charcoal 10 2.1 3.2
Landfills 30 6.4 9.6
Waste water treatment 25 5.3 8.0
Agricultural
Rice 60 12.8 19.3
Livestock 80 17.0 25.8
Manure 10-25 2.1 3.2-7.7
Burning Anon, 2006
Source: 5 1.0 1.6

7. Mitigation of methane from livestock
• Ruminal fermentation time
• Alternate hydrogen acceptors
• Use of feed additives
• Improvement in production efficiency
– Any practice that increases productivity per
animal reduces methane emissions
• Enhancing ruminal acetogens
– Acetogens are a group of rumen microbes
that produce acetic acid from hydrogen and
carbon dioxide rather than methane
• Modification of bacteria in the rumen

8. Fig. Brief outline of the pathways of carbohydrate
fermentation in the rumen
(Source: Preston and Leng, 1986)

9. Effect of improving the efficiency of rumen fermentative activity in
methane production
Effect of supplementation on methane production Effect of bypass protein and other supplements on ruminal
methane production
20 No
supplemen
tation 1200
15
% DE fermented to methane
Urea/miner No supplementation
al
supplemen
800
10
ts
Methane production (Kg/ton Lwt.
Urea/mineral +
gain)
bypass protein
5 400 supplements
0
0
1
1
( Source: Leng, 1991)

10. Effect of improving rumen fermentative activity in methane production
( Source: Leng, 1991)

11. Manipulation of R F with Organic Acids Supplementation
• through treatment of roughage, concentrate and
strategic supplementation with organic acids
• improve rumen efficiency by maintaining higher
pH, optimum ammonia-nitrogen (NH3-N), thus
CH4 and increasing microbial protein synthesis
and essential VFAs
• Recently, there has been increased public scrutiny
about use of antibiotic feed additives in food
animal production, especially in Europe
• Use of organic acids, non-antibiotic feed additives
may alleviate public skepticism

12. Cont’d…
• Organic acids (OAs) have effects on
ruminal fermentation analogous to
ionophores (CH4 , lactate, and propionate)
• However, the mode of action for the organic
acids is different than ionophores
• Organic acids stimulate rather than inhibit
some specific ruminal bacterial populations
• Organic acids that are currently being
evaluated as feed additives are Malic acid,
Fumaric acid, and Aspartic acid

13. Cont’d…
• Recent research showed that a combination of
organic acids ( malate) and monensin
– more effective at reducing lactate
concentrations
– and increasing pH in mixed ruminal
microorganism fermentation than the
addition of organic acid or monensin
alone

14. in vitro studies - response to supplemental malic acid
Response to supplementation
Culture
Treat
system PH TVFA Ac Pr Bu Lac CH NH3-
4 N
Batch (steer)a 0,4,8,12 NE NE NE NE
mM
RUSTIEC 0,5.62 NE NE NE -
(sheep)b mmol
Batch (sheep)c 0,4,7,10 - -
mM
RUSTIEC 0,6.55 NE NE - NE -
(sheep)d mM
Continuous 0,50,100 NE NE NE NE NE NE NE
(dairy g/h/d
cows)e
Up arrow = significant (P<0.01), NE= No effect (P<0.01), a,b,c,d &e= References

15. Effect of supplemental malic acid in dairy cattle (in vivo
studies)
Response to supplementation
DMI Milk milk R. R. R.
Animal Treat yield fat PH VFA CH
4 References
Dairy
cattl
e
Holstein 0,28 , - - - - Stallcup, 1979
70g
Holstein 0,100g - - - Stallcup, 1979
Holstein 10,20 g Khampa et
al.,2006
Holstein 0, 4 g NE NE NE NE A,B,P - Vicini et al.,
2003
Holstein 0,84 g NE - - Devan & Bach,
2004
Up arrow = significant (P<0.01), NE= No effect (P<0.01),

16. Effect of supplemental malic acid in beef cattle and small ruminants
Response to supplementation Reference
DMI Milk milk Gai R. R R. R. s
Animal Treat com n PH . NH CH4
p V 3-N
F
A
Crossbred 0, 40, NE - - - - - - Martin et
steers 80 g al.1999
Angle 0,60,12 NE - - NE - - - - Martin et
steers 0g al.1999
Beef 0, 100g NE - - NE - - - - Martin et
cattle al.1999
HF steers 0,9,18, - - - - NE Khampa et
27g al., 2006
Dairy 0, NE NE NE - - - - - Salama et
goats 0.32% al. 2002
Lambs 0, 0.2% - - - - - Flores et
al.2003
Up arrow = significant (P<0.01), NE= No effect (P<0.01),

17. Manipulation of rumen with Ionophores
• Ionophores are antibiotics includes: monensin,
lasalocid, tetronasin, salinomycin, lysocellin,
narasin, nigericin, laidlomycin and valynomycin
• Since the mid-1970’s they have been
extensively used to manipulate rumen
fermentation
• ionophores are approved in several countries
including Australia, Argentina, New Zealand, and
South Africa and recently USA
• Monensin (trade name Rumensin) widely used
ionophores

18. Cont’d…
• Effect of ionophores on rumen end products
• decrease in hydrogen, a precursor of methane,
• Favors propionate production
• Ionophores inhibit gram-positive bacteria
• major benefit of feeding ionophores to dairy cattle is the
potential increase in production of propionate and the
associated decrease in production of methane, which
conserves energy
•

19. Safety (residual effect)
• Several researchers indicated that meat
and milk produced from animals fed
monensin is safe for human consumption
• Likewise, monensin is biodegradable in
manure and soil, and is not toxic for crop
plants

20. The effects of ionophores on fermentation end products and total ciliate
protozoal populations in Angus yearling steers
•CC= control
•CM=33 mg/kg Monensin
• CM/L= Biweekly rotation
of monensin
(33 mg/kg) and lasalocid
(36 mg/kg)
(Source: Guan et al. 2005)

21. Manipulation of ruminal
fermentation by plant extracts
• Plant extracts have been used for
centuries for various purposes (as
traditional medicine and food
preservatives, among others
• The antimicrobial activity of plant extracts -
secondary plant metabolites (saponins,
tannins, and essential oils)
• selective inhibitors of methanogens

22. Cont’d…
• Plants exhibiting anti-methanogenic
activity include: Equisetum arvense, Lotus
corniculatus, Rheum palmatum, Salvia
officinalis, Sapindus saponaria, Uncaria
gambir and Yucca schidigera
• Major commercial source of saponins is
Yucca schidiger
• Defaunating agent and selective inhibitor-
gram positive bacteria

23. Effect of Yucca Schidigera extract ( Saponins) in vitro ruminal
characteristics and gas production
Yucca schidigera extract (ml/l)
SEM P value
0 2 4 6
pH 6.76 6.79 6.74 6.72 0.02 NS
NH3-N (mg/l) 28.60 21.15 18.19 14.86 1.61 ***
TVFA(mM) 66.45 64.22 67.97 69.24 1.57 NS
VFA (mM)
Acetate (A) 47.71 44.12 45.50 46.26 1.05 NS
Propionate (P) 12.37 14.20 17.07 19.02 0.49 ***
Butyrate 5.69 5.54 4.92 3.64 0.19 ***
Others 0.67 0.35 0.49 0.32 0.11 NS
A:P ratio 4.42 3.88 3.61 3.52 0.06 ***
Protozoa (x104/ml) 13.16 9.38 5.90 5.80 1.07 ***
CH4 (ml/min) 0.24 0.20 0.17 0.14 0.00 ***
CO2 (ml/min) 1.22 1.21 1.39 1.56 0.06 ***
( Source: Pen, 2007)

24. Conclusions
• Rumen manipulation has paramount importance in
improving ruminal fermentation efficiency and
productivity in dairy and fattening ruminants in the
tropics where the major sources of the feed is high
in fibre.
• Rumensin from ionophores and Malic acid from
organic acid are the widely used rumen modifiers in
both dairy and fattening ruminant animals

25. Cont’d…
• Several literatures reported that use of one type
of manipulating technique for prolonged time is
not effective because of adaptation by the
rumen microbes, hence, alternative or rotational
use rather than one alone may be prolonged its
effect in improving the performance of the
animal
• The studies conducted with plant extracts are limited to
in vitro screening for the desired characteristics and only
a few of them have been tested in in vivo experiments

26. Cont’d…
• it is desirable to standardize in vivo dose of
these plant extracts which are effective in
inhibiting methane emission with minimum
adverse effects on fermentation of feed so that
these can be practically exploited for economic
and ‘ecologically friendly’ livestock production

27. Thank You for your kind attention